In cases where a sewer pipe has been buried in soil for many years and aged to be deteriorated in load resistance capacity or water shutoff capacity, there arise problems such as collapse of a road surface and insufficient flow capacity.
In order to solve such problems, there has been proposed and embodied a method of repairing a drain pipe, in which an aged sewer pipe is used as a support and a new resin pipe is inserted thereinto to serve as a drain pipe.
There are various methods of repairing a drain pipe, including the pipe making method, for example, in which a rigid vinyl chloride member in a belt shape is supplied into a manhole, and the rigid vinyl chloride member in the belt shape, which is formed into a pipe shape at an inlet part of an existing pipe with use of a pipe forming machine, is inserted into the existing pipe.
There has been also known the so-called casing pipe construction method in which, in place of the rigid vinyl chloride member in the belt shape, short pipes smaller in diameter than an existing pipe are brought through a manhole and are sequentially connected to each other so as to be inserted into the existing pipe.
However, the pipe making method requires dedicated construction facilities such as the pipe forming machine, and construction in this method needs to be executed by a skilled mechanic. Although the casing pipe construction method does not require such a pipe forming machine, the pipes produced to be used in this method are large in size and thus cannot be easily handled in a narrow manhole. In addition, both of these construction methods require connection work upon forming into a pipe shape in an existing pipe, and such work takes long time in order to enhance sealing performance at the connected parts, which is problematic.
In view of the above, there has been recently proposed a construction method that realizes easy formation of a new pipeline in an existing pipe with no need for any dedicated construction facility. In this method, as shown in FIG. 5, a flexible regeneration pipe 50 having a helically-corrugated surface is fed from a rotary drum 51, is inserted into one end of an existing pipe 53 through a manhole 52, and is drawn through another end of the existing pipe 53 by means of a winch 54 (see Patent Document 1, for example).
In this figure, reference sign 55 denotes a cap attached to the tip of the regeneration pipe 50, and reference sign 56 denotes wire connected to the cap 55.